I think dark matter makes more sense than vanishing time. IMO.
Not dark matter but dark energy. Dark matter has been hypothesized because of the action of galaxies (count the stars and even the black holes to some extent, and it does not account for the effect of gravity (speed of star orbit in the galaxy). Most likely theory for dark matter is a weakly interacting massive particle (WIMP). Something like a neutrino with more mass (or more frequency).
Dark energy comes out of Einstein’s contant for General Relativity. No one has a clue about it, but speculation is that it something like a remainder for quantum energy.
Everyone thinks cosmology is in great shape, but not understanding these two points and basically making something up to fit the observed facts means we have a very long way to go. Slowing of time is just another attempt.
The problem will be is that we are reaching the point where we cannot observe what we need to observe to account for these mysteries. That is no longer science.
Says Time is DisappearingAh ha! I thought I'd merely *misplaced* my Franklin planner...

As a time traveler myself, I can tell you that time is definitely vanishing.
My biggest complaint about my time travel is that I travel through time at the rate of one hour per hour.